Question

Помогите мне срочно пж

Answer 1

$(y^{-2}-x^2)(x^{-1}-y^{-1})=( frac{1}{y^2}-x^2) (frac{1}{x} -frac{1}{y} )=\\=frac{1-x^2y^2}{y^2} cdot frac{y-x}{xy} = frac{(1-xy)(1+xy)(y-x)}{y^3cdot x} \\\(y^{-2}-x^{-2})(x^{-1}-x^{-1})=( frac{1}{y^2} -frac{1}{x^2})( frac{1}{x}-frac{1}{y})=\\= frac{x^2-y^2}{x^2y^2} cdot frac{y-x}{xy} = frac{(x-y)(x+y)(y-x)}{x^3y^3} = frac{-(x-y)^2(x+y)}{x^3y^3}$